Identification particles and system and method for retrospective identification using spectral codes

ABSTRACT

A system and method using reporter elements provides retrospective identification of articles. An article is marked with reporter elements such that the mark has a characteristic spectral response when exposed to energy stimulation. To verify the authenticity of the article, a reader scans the mark containing the reporter elements and obtains a spectral signature. The reader then compares the detected signature to the characteristic signature to determine the authenticity or identity of the marked article.

This application is a continuation-in-part of U.S. Ser. No. 09/897,553,filed Jul. 2, 2001 which is a divisional application of U.S. Pat. No.6,309,690, issued Oct. 30, 2001 and filed Apr. 1, 1999 and acontinuation of provisional application U.S. Ser. No. 60/256,209, filedDec. 15, 2000. Priority is claimed to these applications.

FIELD OF THE INVENTION

The present invention relates generally to the marking of articles forretrospective identification or authentication and more particularly tosystems and methods for marking an article with spectrally codedmaterial and using the characteristic spectral signature of the codedmaterial to retrospectively identify or verify authenticity of markedarticles.

BACKGROUND OF THE INVENTION

Authentication and identification of articles is of great concern in anumber of arenas. For example, customs agents attempt to stop shipmentsof counterfeit goods when they enter the country. To do so, they must beable to distinguish between genuine or authorized goods and counterfeitor unauthorized goods. Attempts have been made to mark authorized goodsand/or their shipment containers and to provide a system for officialsto use the marks to confirm the authenticity of the goods.

Many applications for authenticity-verifying or source-verifyingtechnology require or are benefited from solutions which are easilyimplemented by a person “in the field”. Other applications are benefitedfrom solutions which are easily automated to allow fast yet morecomplete, rather than spot-checked, reviews of larger numbers ofarticles.

What has been needed has been an authentication system with protectionsagainst counterfeiting and with ease of use and access for customsofficials, law enforcement, and other interested persons to verify theauthenticity of articles. The system and method should allow the userseveral different methods to authenticate or identify an item. A neededsystem and method should have varying levels of security, such that afirst magnified “eyeball” review provides some level of assurance thatthe goods are authentic; additional covert features which are moredifficult to verify and more difficult to counterfeit offer furtherlevels of security. Further, the system should be conducive or adaptableto “in the field” applications using hand held or portable verificationor reading equipment. Still further, it is advantageous for anauthentication system to be adaptable to automation, such that articlescan be scanned and authenticated quickly and accurately while minimizinghuman labor.

SUMMARY OF THE INVENTION

In a preferred system and method according to the present invention, oneor more reporter elements is applied to an article, item or a label forwhich retrospective identification is desired. Upon excitation orstimulus, such as from an energy source, the reporter elements yield aspectral “signature” that characterizes the reporter elements' responseto the stimulus. To verify the authenticity of the subject article, themicroparticle mark is scanned with a device that “reads” the spectralsignature of the reporter elements and determines whether the detectedsignature matches the pre-defined signature. The reader displays anindication that the article is authenticated.

In another embodiment, the spectral signature of reporter elements to beapplied to an article is read, and is translated via an algorithm to aprintable code, such as an alpha-numeric code or a bar code, that isthen printed on the article or on the label bearing the mark. Thedetector uses the same algorithm to decipher the code and displays thisdeciphered code, and the user then reads the code displayed on thereader device and compares that to the printed code. If the decipheredcode matches the printed code, then the article is authentic. As anadditional feature, a serial number or otherwise unique code is added tothe deciphered code from the spectral signature. In this manner, eachmarked article is uniquely identifiable by its serial number, as well asbatch identifiable by its spectral code.

Preferably, one or more reporter elements are incorporated into one ormore layers of a microcoded particle or are applied in conjunction witha microcoded particle.

The system and method of the present invention can be used inconjunction with the pattern recognition in the manner described in U.S.Ser. No. 09/283,174, filed Apr. 1, 1999, issued as U.S. Pat. No.6,309,690, incorporated herein by reference in its entirety.

In another preferred embodiment, the microparticles have distinctlycolored layers and the sequence of the colored layers forms a code thatis assigned to a particular meaning, such as the source or identity ofgoods marked with the particles. The colors of the microparticles may beselected advantageously to have some common association to the article.

In another preferred embodiment, the microparticles have indicia on orbelow the surface of the particle. Preferably the indicia is embossed,laser etched, photo reduction, or the like.

These preferred embodiments enable a variety of methods of“interrogating” the microcoded marks to confirm the authenticity of thearticle. Some of the embodiments have at least one level of securitythat can be viewed and assessed with simple magnification. Otherembodiments require exposure of the mark to an energy stimulus, such astemperature changes, light, or electric current induced by magneticfield.

These preferred embodiments enable varying degrees of security againstcounterfeit.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary version of a microcoded mark and a system and method forauthenticating articles is shown in the figures, wherein like referencenumerals refer to equivalent structure throughout, and wherein:

FIG. 1 is a schematic illustration of a system and method for marking anarticle for retrospective identification with reporter elements;

FIG. 1 a is a schematic illustration of a system and method for markingan article for retrospective identification with reporter elements and aprintable code computed from the spectral response of the reporterelements;

FIG. 2 is schematic illustration of the generation of a spectralsignature for spectral code containing three types of reporter elements;

FIG. 3 is a schematic illustration of an alternate version of the systemand method illustrated in FIG. 1;

FIG. 4 is a schematic illustration of a system and method forinterrogating a label to determine its authenticity, where the label orarticle has been marked in accord with the system and method of FIG. 1a;

FIG. 5 is a schematic illustration of a system and method forinterrogating a label to determine its authenticity, where the label orarticle has been marked in accord with the system and method of FIG. 1 aand with a bar code;

FIGS. 6 a-6 d are schematic illustrations of alternate arrangements forincorporating reporter elements in one or more layers of a microparticleor microcoded particle;

FIG. 7 is a an enlarged side view of a microparticle used in accordancewith the present invention; and

FIG. 8 is an enlarged perspective view of an embodiment of amicroparticle used in accordance with the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

A preferred system and method for retrospective identification of anarticle 5 or a container of articles using spectral signatures accordingto the present invention is illustrated schematically in FIGS. 1-6. FIG.1 illustrates a magnified mark 12 that is generally undecipherable tothe naked eye. That is, it may be apparent that the mark is present, butthe detailed aspects of the mark are not visible without magnificationor digital imaging. The mark 12 incorporates reporter elements 14. Areporter element 14 is any atom, molecule, crystal, polymer or othercompound or the like that interacts with a form of energy, such aslight, to give a detectable light emission or absorption response.Reporter elements 14 are described in greater detail below in thesection entitled “Reporter Elements”. Examples of the many manners inwhich reporter elements 14 can be incorporated into the mark 12 and thematerials that can be used for reporter elements 14 will be described ingreater detail below.

The mark 12 can be applied to, affixed to, mixed into, or otherwiseconnected to the article 5 to be retrospectively identified. Of course,the manner of that connection will be determined in many cases by thenature of the article 5. For example, if the article 5 is a powderedmaterial, such as that used in an explosive compound, the reporterelements 14 can be directly mixed into the powder. Alternatively, aswill be described below, the reporter elements 14 can be embedded withina microcoded particle, and these microcoded particles can be mixed intothe explosive powder. For other applications, it will be desirable toaffix the reporter elements (within a microcoded particle or alone) to alabel that is adhered to an article. Still further, it may be desirableto incorporate the reporter elements (within a microcoded particle oralone) in an adhesive or an ink, or the like which is then applied to alabel or article, as depicted in FIG. 1 a. Microcoded particles ormicroparticles are described in greater detail below in the sectionsentitled “Microcoded Mark”, and the incorporation of reporter elementswithin a microcoded particle is described below in the “ReporterElements” section.

Preferably reporter elements of one or more types are mixed to yield abatch of “spectral code” 16. Each type of reporter element has acharacteristic absorption/emittance response to energy stimulation.Variable concentrations of reporter elements can be used to provideunique emission intensities. The spectral signature of a mix of two ormore elements contains the additive combination of the spectral responsesignatures of each included element or type. Typically, this additivecombination yields a response and peak over one wavelength range for oneelement, and a response and peak over another wavelength range for asecond element, and so on. In other words, the types are chosen suchthat their responses are distinct; each type responds across a differentwavelength than other type or types within the batch.

As illustrated in FIG. 2, a sample 18 of the batch of spectral code 16is exposed to an energy excitation source 20, such as light or heat, towhich the reporter elements A, B, and C 14 respond. A spectral analyzer22 reads the response of the reporter elements 14 and generates aspectral signature 25 displayed in a graph showing intensity as afunction of wavelength. Alternatively, the analyzer generates a spectralsignature displayed in a graph of intensity as a function of frequencyor wavelength. As another alternative, the spectral signature could bedisplayed in a graph of the sum of two or more of these functions orother mathematical manipulation of any of these signatures orcombinations of the signatures.

Each type of reporter element 14 shows a maximum or peak response withinor across a predetermined range of wavelengths. In the illustratedexample, three types of reporter elements, A, B and C, yield threecorresponding maximum intensity peaks I_(A), I_(B) and I_(C) atwavelengths λ_(A), λ_(B) and λ_(C), respectively. The intensity of theresponse of each type of reporter element 14 depends upon itsconcentration in the sample 18. Upon interrogation, a detector is usedto observe the spectral response of mark made of sample 18. The detectorpreferably provides an indication of whether the detected signaturemeets the pre-defined signature for sample 18.

The system and method can use either or both of the parameters ofwavelength and intensity to characterize the spectral signature of asample 18. In other words, the signature might be defined such that anintensity peak must be exhibited at a particular wavelength or between arange of wavelengths, but the actual values of the intensity might beignored. Alternatively, for added security or precision inidentification, the signature might be defined such that a particularintensity maximum must be exhibited at a specified wavelength or withina range of wavelengths. As another alternative, the intensity alonemight be used: i.e., if the intensity of the response is not at orsufficiently near a specified intensity value, then the conclusion canbe drawn that the specified reporter element is not present in theconcentration required of an authentic sample.

For some types of reporter elements 14, other aspects of a spectralsignature can be used. For example, the spectral response of fluorescentor phosphorescent materials is time-dependent, with the maximumintensity of its response diminishing over time after the removal of anenergy stimulus. Thus, these materials have a characteristic half-life.The time-dependent signature can be characterized through relativelyrapid serial analysis of the emission signal.

An optional feature which offers additional security advantages includesthe transposition of the spectral signature into an alpha-numeric codeor other type of printable code, such as a bar code. This is illustratedin FIG. 1 a in conjunction with an application involving a mark on alabel 10′, though this printed code aspect might also be used inconjunction with applications that do not involve a label. Asillustrated in FIG. 1 a, the spectral signature 25′ is filtered throughan algorithm 30′ to transpose the signature 25′ into a printable code50′, such as an alpha-numeric code or a bar code. A printer 40′ printsthis printable code 50′ on the label 10′. Further, the printable code50′ is stored in a database 60′ in conjunction with a description of thegoods on which the printable code 50′ is placed. Optionally, thedatabase 60′ may assign a unique identifier 70′, such as a serialnumber, to the article and the printer 40′ can print that uniqueidentifier 70′ on the label 10′. In one embodiment, the serial number70′ and the printable code 50′ are joined into one string(alpha-numeric, bar-code or other) that is printed on the label 10′.Optionally, the label 10′ also includes human-readable writtenidentification or description 80′ of the goods.

FIG. 3 illustrates an alternative order for initial steps in the markingof an article. In the FIG. 3 embodiment, the mark 12 is first applied tothe article 5 (or on a label 10′) and then scanned by a spectralanalyzer 22 to determine the spectral signature of the mark 12, or morespecifically of the reporter elements 14 in the mark 12. The rest of thesystem and process depicted in FIG. 3 is the same as that depicted inFIG. 1 and described above.

FIGS. 4 and 5 illustrate ways that an article 5, marked in the mannerillustrated in FIG. 1 a, can be interrogated to determine theauthenticity of the article 5. As shown in FIG. 4, a reader or detector100′ images the mark 12′ and computes the printable code 50′ byperforming the designated algorithm 30′ on the spectral signature. Adisplay 105′ on the reader 100′ displays the computed code. The user110′ views and compares the computed code with the code 50 printed onthe article or on a label 10′ affixed to the article. In the illustratedcase, the mark and code both appear on a label 10′ which is coupled withthe article to be identified. If the codes match, then the article islegitimate. Preferably, in a label configuration, the label 10′ istamper-evident, such that if a legitimate label is removed from itsoriginal location, the mark 12′ is destroyed or altered, such thatspectral analysis and decoding of the altered mark 12′ will not yield acomputed code that matches the printed code 50′.

In another embodiment, illustrated in FIG. 5, a reader 150′ scans themark 12 and a serialized barcode 155′ printed on the article or a labelaffixed to the article. If these components “match”, then the reader150′ gives an indication of a match, such as with an indicator light160′. The components match if they are stored in conjunction with oneanother in the database 60′.

FIGS. 4 and 5 illustrate analysis via a generally portable device, withthe mark 12 being reviewed without disturbing its attachment to thearticle. In some cases, however, it may be advantageous to extract thereporter elements to perform other types of analysis not conducive toportable equipment or to “in the field” methods or technology.

Technology and methods that can be used for spectral analysis are wellknown to those of skill in the art, and include, for example:chromatography, mass spectroscopy, nuclear magnetic resonance, infraredspectroscopy, ultraviolet/visible spectroscopy, flame ionization,electrical analysis, thermal analysis, hybridization assays, gelelctrophoresis.

Reporter Elements

As described above, a reporter element can be any molecule, crystal,atom or compound, including polymers, that, when stimulated by energy,yield a detectable energy, mass or other response. For light responsivereporter elements, materials can be used which are responsive to anydesired frequency or wavelength. The response of the reporter element isdependant upon the material of the reporter element as well as theenergy stimulus provided but typical responses include fluorescence,phosphorescence, upconverting phosphorescence, absorption and emission.

As will be understood, the material used for the reporter element, theappropriate energy stimulus, and the response of the reporter elementare copescetic. The following chart provides examples of materials,energy stimuli and responses: Material - Any material from the followingfamily of materials: Energy Stimulus Response Flourescents Light Light(Fluorescence) Phosphorescents Light Light (Phosphorescence)Upconverting Light Light phosphorescents Photochromics Light Light ofpredetermined wavelength Thermochromics Heat/Cold Light ElectrochromicsElectric current Light Infrared fluorescents Light in infrared Light(Fluorescence) wavelengths Infrared phosporescents Light in infraredLight (Phosphorescence) wavelengths Near-infrared fluorescents Light inLight (Fluorescence) near-infrared wavelengths Semi-conducting LightLight nanocrystals (e.g. from the group II-VI such as cadmium selenideCdSe, magnesium selenide MgSe, calcium selenide CaSe, barium selenideBaSe, zinc selenide ZnSe) Magnetic resonance Magnetic field Nuculearmagnetic molecules resonance (NMR) frequencies Isotopic isomers orreally Electrical energy Mass detection any atom, ion, molecule

The semiconducting nanocrystal family offers advantages of stability(i.e. increased shelf life), relatively narrow emission spectra,relatively broad excitation spectra, and can be excited withoutlaser-generated light.

As illustrated in FIG. 6, reporter elements 14 can be implemented incombination with a microcoded particle or substrate in a variety of waysto form an identification particle. Generally, a microcoded particle isa multilayered particle. Microcoded particles are described in greaterdetail below.

FIG. 6 a shows a microcoded particle 200, with reporter elements 214entrained in the outer layers 220 and 221 of the particle 200.

FIG. 6 b shows an arrangement wherein reporter elements 214 areentrained in carrier material 230, such as adhesive, ink or othermaterial, in which microparticles 225 are entrained, but where thereporter elements 214 are separate and distinct from the microparticles225.

FIG. 6 c shows an arrangement wherein one type of reporter element isincorporated into one layer of a microparticle 250. More specifically,reporter element 214A is entrained in a first layer 260; reporterelement 214B is entrained in second layer 270; and reporter element 214Cis entrained in third layer 280.

FIG. 6 d shows an arrangement wherein a single layer substrate 290contains the reporter elements 214, preferably of two or more types214A, 214B, 214C. In some applications, it may be advantageous to addembossing of a bar code or other indicia to the surface of the substratefor additional identification properties.

While all of these examples of FIGS. 6 a-6 d illustrate theincorporation of three types of reporter elements, it will be understoodthat any number of reporter elements can be used. For the example ofFIG. 6 c, the layers could contain the same type of reporter element,but in varying concentrations in adjacent layers. Further, themicrocoded particle might contain one or more layers without anyreporter elements therein.

The Microcoded Mark

The use of microparticles for the retrospective identification ofarticles is known from U.S. Pat. Nos. 4,053,433 and 4,390,452,incorporated herein by reference, and from other sources. Such particlesmay be used for the identification of a wide variety of items. Eachmicroparticle includes a sequence of visually distinguishable dyedand/or pigmented layers. The microparticles are “coded” in the sensethat particular color sequences in the particles are assigned to aparticular meaning, such as the source of the item on which theparticles are placed. Typically, microparticles are not “readable” tothe naked eye, i.e. the particles must be magnified for the layersequence to be discerned.

FIG. 7 shows a microparticle 1090. The particle 1090 has top and bottomsurfaces 1091 and 1092, with two or more layers 1093, 1094 therebetween.An edge 1095 extends between the top and bottom surfaces andcircumscribes the particle. The edge 1095 is generally irregular. Whilethe depicted microparticle has only two layers, the microparticle maycontain any number of layers.

In a preferred embodiment, energy-sensitive materials, such asthermochromic or photochromic materials, may be used for one or more ofthe layers. An energy-sensitive material has different opticalproperties under different conditions. For example, a thermochromicmaterial is transparent in one temperature range, but opaque outside ofthat range. Photochromic material can be transparent or one color underwhite light of a range of frequencies, but a different color whenexposed to light outside of that range of frequencies. Use ofenergy-sensitive material for all of the layers aids in making themicrocoded mark covert. That is, if the layers are of thermochromicmaterial having the property of being transparent at room temperature,and if the particles are entrained in a generally transparent adhesiveor epoxy, then the microcoded mark will be generally covert at roomtemperature. The mark and the sequence of its colored layers can berevealed by exposing the mark to an elevated or decreased temperature,depending upon the predetermined properties of the thermochromicmaterial.

In another preferred embodiment, near-infra-red-frequency material isused in the microparticle. Such material flouresces when exposed toinfra-red light. Use of this material aids in making the microcoded markcovert. Currently, known infra-red materials lose their responsivenessover time upon exposure to UV light. Therefore, in a preferredembodiment of these microparticles, a near-infra-red-frequency layer iscovered by or sandwiched between energy sensitive layers that are opaqueat typical indoor ambient temperatures to protect the near-infra-redmaterial from exposure to UV light under typical temperature conditions,thereby prolonging the life of the near-infra-red material.

In another preferred embodiment, magnetic materials or other materialsthat exhibit unique NMR spectrum are used in the microparticle.

In another embodiment, the microcoded particle may be a one or morelayers that may be clear or colored and may include indicia thereon. Theindicia may be produced by laser etching, embossing, photo reduction, orthe like. Reporter elements may be entrained in the layer or substrate.

In another preferred embodiment, illustrated in FIG. 8, an outer surfaceor visible layer 1096 of the multi-layered microparticle 1097 bearsindicia 1098, such as alpha-numeric characters, patterns, abstractimages or the like. The indicia are preferably registered. A typicalmethod of forming microparticles bearing indicia yields slightlyrecessed indicia. Such a method involves laser etching or embossing ofthe indicia onto the outer surface of the microparticles. Another suchmethod is described in U.S. Pat. No. 4,390,452. To enhance thevisibility of the recessed indicia, the method may also include a stepof applying a curable ink to the indicia-bearing surface, wiping the inkaway, leaving ink settled in the recesses, while leaving the un-recessedarea substantially ink-free. When a curable ink is used, the particlecan then be cured, and the ink will solidify and the ink-filled indiciaare then more easily discernable. For example, inks that cure uponexposure to ultraviolet can be used.

The “code” of the microparticles aids in the retrospectiveidentification of the article because a particular code can be assignedto a specific article, application or customer. The code is retired, andparticles bearing this sequence or indicia will not be used in aconflicting manner. Retrospectively, the microcoded mark can be viewedunder magnification and, using information stored in a database, matchedwith the information relating to that particular color sequence orindicia revealing that the article matches the article to which thatsequence is assigned.

The Detector

A reader or detector 100, 100′ or 150 incorporates hardware that linksit to the computer on which the algorithm 30 and database 60 are storedso that it can access the relevant algorithm 30 as well as data from thedatabase 60 regarding the subject goods, such as a textual descriptionor serial numbers. This link can be made via the internet or viahardwire or any other method of transferring digital information.Preferably, security features allow access to the database and algorithmonly to selected users.

The detector can also be used to read barcodes on labels, identify thelocation of reporter elements in a microcoded particle. The detector mayinclude a video monitor to view an image of the area being examined ordisplay the results of each test.

The preferred detector contains an excitation source to provide thestimulus needed to generate the signature response from the reporterelements.

One embodiment of the detector includes a cycling mechanism such thatthe excitation stimulus and response detection are pulsed or timed. Thisoffers particular advantage when used to detect half-life signatures.

Preferably, a detector is capable of detecting a wide range ofwavelengths of light to accommodate a variety of types of reporterelements. Filters, photomultipliers, resistors and the like can be usedto accomplish this.

Preferably, the detector has circuitry that allows for the analysis ofthe spectral signature in a variety of ways. At a basic level, if alltypes of expected reporter elements are present, the detector yields a“yes” or “no” answer. A more sophisticated detector yields more detailedanalysis, such as indicating the presence of individual types ofreporter elements.

The detector can indicate whether the detected reporter elements “match”the expected, predefined signature in various ways. For example, coloredLEDs can be incorporated. Red and green LEDs can be used to indicate ayes/no determination. Alternatively, several LEDs of various colors cancorrespond to each colored layer in a microcoded particle.

Although an illustrative version of the method and system is describedbelow, it should be clear that many modifications to the method andsystem may be made without departing from the scope of the invention asexpressed in the appended claims.

Throughout this description, the following terms include the meaningsascribed to the terms by those of ordinary skill in the art and includesmeanings now understood and those yet to be discovered or applied; theterms include, but are not limited to, at least the followingillustrative meanings:

Data means textual, numeric, graphic, symbolic or any other information.

Input device includes a keyboard, mouse, track ball, stylus,touch-sensitive screen, touch-sensitive cursor or mouse pad, or voicereceiver and recognition apparatus/software or any other device nowknown or yet to be developed for a human to interact with a digitalstorage medium to input or access data stored therein.

Storage medium means any method of storing information for later use,particularly in connection with digitized information, including but notlimited to a floppy disk, a hard drive, digital tape, and compact disk.

Network means any connection between two computers by which one computercan send or access information stored on another computer, including butnot limited to hard-wired connection, modem/phone line connection,modem/satellite connection, and RF connection.

Database means an organization and storage system for records, whereinone or more pieces of information are stored for each record.

Indicia or indice means numeric characters, alpha-numeric characters,Roman numerals, abstract images, barcodes, logos, patterns and the like.Indices may be serialized or not serialized.

Label means an image-bearing medium, whether optical or mechanical,including but not limited to paper, foil, or multi-layer configurations.

1-20. (canceled)
 21. An identification system, comprising a) a particleincorporating a code; b) a carrier material entraining the particle; andc) a reporter element incorporated into the entraining carrier material,said reporter element emitting a spectral signature responsive to energystimulation.
 22. The system of claim 21, wherein the particleincorporates a sequence of colored layers, wherein the sequence of thecolored layers provides the code.
 23. The system of claim 21, whereinthe reporter element is phosphorescent.
 24. The system of claim 21,wherein the reporter element is fluorescent.
 25. The system of claim 21,wherein the reporter element is photochromic.
 26. The system of claim21, wherein the reporter element is thermochromic.
 27. The system ofclaim 21, wherein the reporter element is an up-convertingphosphorescent material.
 28. The system of claim 21, wherein thereporter element emits a spectral signature responsive to an infraredenergy stimulation.
 29. The system of claim 21, wherein the reporterelement is a semiconducting nanocrystal.
 30. The system of claim 21,wherein at least two reporter elements are incorporated into theentraining carrier material, said two reporter elements having adifferent spectral response to energy stimulation.
 31. A method ofmaking a coded particle, comprising the steps of: a) causing a codedparticle to be entrained in a carrier material; and b) causing areporter element to be entrained in the carrier material.